With approximately 20 million dengue cases a year and 100 countries affected, the World Health Organization considers dengue the most important mosquito-borne viral disease. A vaccine is not currently available and mosquito control is a critical element of dengue disease prevention. There are reports that conventional ground and aerial application of insecticides are not providing adequate control of the mosquitoes that transmit dengue. Dengue is primarily transmitted by the Aedes species of mosquito. The Aedes mosquito is a container breeder and, therefore, the female Aedes mosquito will only lay eggs in a container holding water.
Chemical mosquito control has relied on area treatment of the mosquitoes' habitat. For example, large outdoor areas or the space within a home are treated with an insecticidal fog or spray in an attempt to deposit a lethal dose of insecticide on individual mosquitoes. The water used as mosquito breeding habitats has also been treated with insecticide which is designed to kill the developing larva. Adult resting places have been treated with an insecticide deposit designed to kill adult mosquitoes as they stand on the resting places.
The oviposition trap (hereinafter "ovitrap")has been used as a surveillance tool for Aedes mosquitoes. The ovitrap consists of a pint sized water container, filled with water to within 1 inch of the top, with a wooden or velour paper paddle projecting above the water surface. Aedes females are attracted to the ovitrap and deposit eggs on the paddle. The number of eggs deposited provides an indication of the Aedes mosquito population.
A variation of the ovitrap in described in U.S. Pat. No. 5,123,201. This patent describes a sensor-triggered suction trap for collecting live gravid mosquitoes. When a mosquito interrupts an infrared beam a fan is activated which blows the mosquito into a container for collection. Such a device is complicated and expensive. Furthermore, this device does not kill mosquitoes or mosquito larvae.
Chan, K. L., et. al., "An autocidal ovitrap for the control and possible eradication of Aedes aegypti", Southeast Asian Journal of Tropical Medicine and Public Health, 8(1), pages 56-62 (1977), discloses a modified ovitrap in which any eggs that hatched would be unable to emerge as adults because of a mechanical barrier. By slowly trapping and killing progeny of Aedes aegypti there was a gradual reduction of the population.
U.S. Pat. No. 4,328,636 describes a foraminous barrier which prevents hatched mosquitoes from escaping a body of water. Such a trap, which allows adult females to escape, does not directly interrupt the dengue transmission cycle since adult females can leave the trap after depositing their eggs and take another blood meal, possibly transmitting dengue.
Ikeshoji, T., et. al., "Surfactants for a mosquito ovitrap", Jap. J. Sanit. Zool., 28(4), pages 451-452 (1977), relates to the use of surfactants to drown adult mosquitoes as they attempted to lay eggs. This method is a research tool and not a control method.
Obaldia, G. Davila de, et. al., "Aedes aegyti resting preference on untreated and deltamethrin-treated crepe paper and plastic foam surfaces", J. Am. Mosq. Control Assoc. 12(3), pages 467-68 (1996), investigated the use of resting boxes having insecticide impregnated surfaces. Shortcomings of such a control method are that there are many resting stations to compete with and females would be able to lay eggs prior to entering the resting box, ensuring a next generation.
There is a need for an environmentally sound, simple, cost-effective apparatus and method for controlling populations of the Aedes species of mosquito, primarily Aedes aegypti and Aedes albopictus.